1 files changed, 39 insertions, 0 deletions
diff --git a/src/mbgl/util/tile_coordinate.hpp b/src/mbgl/util/tile_coordinate.hpp
new file mode 100644
index 0000000000..9962c35b18
--- /dev/null
+++ b/src/mbgl/util/tile_coordinate.hpp
@@ -0,0 +1,39 @@
+#ifndef MBGL_UTIL_TILE_COORDINATE
+#define MBGL_UTIL_TILE_COORDINATE
+
+#include <mbgl/style/types.hpp>
+#include <mbgl/map/transform_state.hpp>
+
+
+namespace mbgl {
+
+class TransformState;
+
+// Has floating point x/y coordinates.
+// Used for computing the tiles that need to be visible in the viewport.
+class TileCoordinate {
+public:
+    double x, y, z;
+
+    static TileCoordinate fromLatLng(const TransformState& state, double zoom, const LatLng& latLng) {
+        const double scale = std::pow(2, zoom - state.getZoom());
+        return {
+            state.lngX(latLng.longitude) * scale / util::tileSize,
+            state.latY(latLng.latitude) * scale / util::tileSize,
+            zoom
+        };
+    }
+
+    static TileCoordinate fromScreenCoordinate(const TransformState& state, double zoom, const ScreenCoordinate& point) {
+        return fromLatLng(state, zoom, state.screenCoordinateToLatLng(point));
+    }
+
+    TileCoordinate zoomTo(double zoom) const {
+        double scale = std::pow(2, zoom - z);
+        return { x * scale, y * scale, zoom };
+    }
+};
+
+} // namespace mbgl
+
+#endif